The inventors of the present invention have already disclosed a prior-art packing filler of the aforesaid type in Patent Document 1.
Patent Document 1: JP-A-2003-40335
As shown in FIGS. 5 and 6, the prior-art packing filler is a body formed from a tubular resilient net material 22 having opposite end portions one of which is open and the other of which is defined as a bound portion 21. The packing filler includes an annular roll portion 23 formed by folding the open end portion outward and rolling up the net material 22 toward the bound portion 21. The bound portion of the prior-art packing filler is formed by fusion-bonding the other end portion of the net into a flat disk shape.
The bound portion 21 of the prior-art packing filler projects above the annular roll portion 23 before the packing filler is filled in an upper space of a container. The packing filler can be easily squeezed into the container by holding the bound portion 21. However, when a cap is attached to the container, the bound portion 21 is depressed by the cap as shown in FIG. 7, whereby only the outermost layer 24 of the annular roll portion 23 is correspondingly bulged to be slacked. With only the outermost layer 24 thus bulged, a cushioning effect for tablets contained in the container is significantly reduced. Further, the tablets are likely to enter a center net portion of the bulged outermost layer 24. Therefore, when the packing filler is removed from the container, the tablets are likely to be inadvertently taken out together with the packing filler and scattered on a floor. If the outermost layer 24 is bulged upward as well as downward when the bound portion 21 is depressed, the bulged net portion is likely to be caught between a container mouth and the cap attached to the container.